This invention relates to anchor pile connectors and in particular to releasable connectors for securing the tension legs of a tensioned leg platform. After an offshore well is drilled from a floating platform, it may be desirable to produce the well to a later-installed tensioned leg platform. These platforms, while supported by the buoyancy of the water, are not freely floating but are tied back to a plurality of anchors and tensioned from the seabed. Typically, a plurality of tension lines are located at each corner of the platform and all are maintained continuously in tension although the amount of tension may vary and the lines may vary up to 15 degrees from the vertical at the anchor location.
An anchor template is secured to the seabed with driven and/or drilled and cemented piles. The tension legs are run from the various anchor templates to the platform. Each is typically a 23 cm OD by 8 cm ID tubular member in threaded sections, operating under a nominal tension of 1,000 tons. For the purpose of inspecting these lines at a later date, it is desirable to retrieve the entire string of a particular leg while the remaining legs continue to carry the load.
Other anchor connectors for tensioned leg platforms are based on an arrangement where the anchor locks only if there is continued tension. A loss of tension resulting in a reversal of forces at the connector operates to disconnect the leg with possible subsequent damage to the platform and equipment operating from the platform. Other possible schemes considered require complex operating mechanisms and structures which result in stress concentrations in the connector. Furthermore, it is helpful to have a connector which can be disconnected with diver assistance in the event that the primary disconnect apparatus malfunctions.